The present invention relates to a network system and a communication device. Particularly, the present invention relates to a network system with ATM (Asynchronous Transfer Mode) communication devices such as ATM-HUB/ATM handler/ATM router/ATM switching unit accomodating line interfaces (NNI/UNI) of the ATM layer such as SDH/SONET/E3/DS3 (HEC/PLCP) for B-ISDN (Broadband-Integrated Service Digital Network).
In late years, as multi-media advances, B-ISDN receives attention as a leading part for next-generation communication network. Thus, it is expected that B-ISDN is used for a big and complicated network such as WAN (Wide Area Network) and OCN.
Accordingly, as for ATM communication device connected to B-ISDN, when it is expected that a communication failure occurs during the maintenance is operation, it is desirable to previously communicate contents of the communication failure to a transmission device (such as another ATM communication device and terminal) connected to another B-ISDN.
Here, in the conventional network system, concerning communication failures occurring between segments or end-to-end, the ATM communication device constituting a network notifies and detects line failures according to the following protocol so as to manage communication quality of NNI (Network Node Interface)/UNI (User Network Interface).
That is, in the conventional network system, when an ATM communication device to be a receiving device detects a communication failure such as LOS (Loss Of Signal)/LOF (Loss Of Frame)/OOP (Out Of Frame)/LOP (Loss Of Pointer)/LOP (Loss Of Cell) prescribed by SDH/SONET/E3/DS3 (HEC/PLCP), the ATM communication device transfers a failure alarm such as MS-RDI, P-RDI or P-YELLOW to an ATM communication device to be an opposing device. Then, the ATM communication device which receives a failure alarm performs the process corresponding to the failure alarm.
However, in the conventional network system, there are following problems. That is, in the conventional network system, for example, as to any ATM communication device constituting this network system, when there is a phenomenon independent of line quality such as stop by outage and a operator, an ATM communication device to be an opposite device to that ATM communication device detects a communication failure such as LOS/LOF/OOF/LOP/LOC.
However, LOS/LOF/OOF/LOP/LOC are information showing only a condition of the communication failure in the network but a cause of the communication failure. Thus, it is impossible for the ATM communication device which has detected the communication failure to know whether this communication failure is caused by quality deterioration of the network system (such as failure of ATM communication device and degradation of cable) or is caused by another cause (above-mentioned outage and stop of hand oprated power supply). As the result, in the conventional network system, there is a case that it is impossible for an ATM communication device which has detected a communication failure and an administrator of the communication device (an administrator of the network system) to deal with the communication failure according to the cause thereof.
The present invention is achieved in view of the above-described problems, and has as its object the provision of a network system and a communication device capable of dealing with communication failures more suitably than the conventional network system and communication device.
The present invention introduces the following aspects to solve the above-described problems. That is, the first aspects of the present invention is network system in which a first communication device and a second communication device are connected through a communication line. The first communication device comprises a detection unit detecting an device failure caused in the first communication device, a notification unit gererating device failure information about the device failure detected by the detection unit and transmitting the device failure information to the second communication device, and the second communication device comprises the receiving unit receiving the device failure information from the first communication device, the memory unit memorizing the device failure information received by the receiving unit, and a display control unit displaying the failure alarm and the device failure information memorized in the memory means.
According to the first aspect of the present invention, when device failure causes in the first communication device, the first communication device transmits the device failure information to the second communication device. The second communication device makes a display unit display the device failure information. Thus, the administrator of the second communication device or the administrator of the network system, when the communication failure causes between the first communication device and the second communication device, can clearly know that the communication failure is caused by the device failure of the first communication device. Thus, the administrators can deal with the communication failure appropriately.
Here, the device failure is, for example, that power supply of the first communication device is stopped by human power, that electric power to be supplied to the first communication device by a power source lowers than a predetermined value, that a registration of the communication line connecting the first communication device and the second communication device is canceled by a operator and that the communication line is physically cut by external power as the device failure.
As to first aspect of the present invention, it is preferable that the detection unit detects communication failure caused between the first communication device and the second communication device, and the notification unit generates failure alarm information about the communication failure detected by the detection unit and transmits the failure alarm information to the second communication device, and the receiving unit receives the failure alarm information from the first communication device, and the memory unit memorizes the failure alarm information by the recceiving means, and the display control unit makes a display unit display the failure alarm information memorized in the memory means.
As to first aspect of the present invention, it is preferable that further comprises a another communication device connecting to the second communication device through the communication line, and the second communication device, when the device failure information is memorized in the memory unit, transmits information equal to the device failure information to the another communication device. In this case, it is possible to transmit the device failure information to another communication device downstream from the second communication device. As another communication device, a transmission unit or a terminal equipment is also used. In addition, when a plurality of other communication devices are connected to the second communication device, it is preferable that in-device failure information is multi-cast to these communication devices.
Further, in the first aspect of the present invention, it is preferable that the first communication device and the second communication device are ATM communication devices. As ATM communication devices, it is possible to mention an ATM-HUB, an ATM router, an ATM handler, an ATM switching unit and so on. In this case, it is preferable that the notification unit generates a operation and maintenance cell storing the device failure information and transmits the cell to the second communication device and that the memory unit memorizes the device failure information extracted from the operation and maintenance cell.
The second aspect of the present invention is a communication device connected to another communication device through a communication line. The communication device comprises a receiving unit receiving device failure information about device failure caused in the another communication device from the another communication device, a memory unit memorizing the device failure information received by the receiving means, and a display control unit making a display unit display the device failure information memorized in the memory unit.
The third aspect of the present invention is a communication device connected to another communication device through a communication line and making a display unit display device failure information. The communication device comprises a detection unit detecting device failure caused in the communication device, and a notification unit gererating device failure information about the device failure detected by the detection means and transmitting the device failure information to the second communication device.
According to the network system and the communication device of the present invention, it is possible to know that a communication failure occurring between communication devices is caused by the device failure of one communication device from the other communication device, therefore, it is possible to deal with the communication failure appropriately.